Tire preparation ply manufacturing apparatus and method

ABSTRACT

An apparatus for forming a continuous preparation ply of the type used to make vehicle tires from preparation ply sections having nonmetallic cords. An infeed conveyor successively feeds the preparation ply sections to a butt splicing machine that joins the ends of the two preparation ply sections to form a butt joint. A gum strip applier receives the continuous preparation ply from an outfeed conveyor and applies a gum strip over the butt joint. A method is provided for forming a continuous preparation ply by first automatically forming a butt joint, and thereafter automatically placing a gum strip on the butt joint.

FIELD OF THE INVENTION

[0001] This invention relates generally to apparatus and method forproducing a continuous preparation ply material for making tires andmore particularly, to an apparatus and method for making a continuousweb of preparation ply material having transverse nonmetallicreinforcing cords.

BACKGROUND OF THE INVENTION

[0002] In the construction of a radial ply tire, a carcass consisting ofone or more preparation plies of elastomeric material is built up on agenerally cylindrical drum. The preparation ply is applied so thatreinforcing cords run from bead to bead in a direction that is generallyparallel to the axis of the drum. Thus, prior to making the carcass, thepreparation ply with the transversely extending reinforcing cords mustfirst be made.

[0003] It is known to manufacture the preparation ply by first producinga sheet of elastomeric material in which reinforcing cords extendlongitudinally. During production, the sheet of elastomeric materialpasses between calendering rolls. The calendered sheet of material isthen cut into quadrilateral, for example, rectangular pieces, reorientedand the calendered edges are then spliced together to form a continuousstrip of preparation ply material. The reorientation results in thereinforcing cords extending substantially parallel to the splice jointsand substantially perpendicular to the longitudinal direction of thepreparation ply strip.

[0004] If the elastomeric material has metallic reinforcing cords, thelateral calendered edges of the material have relatively straight anduniform edges. Thus, in the manufacture of a preparation ply that hasmetallic reinforcing cords, the adjacent ends of the strips are placedin direct opposition and brought together without any overlap of theends to form an end-to-end or butt joint splicing the two ends together.Thus, the ends are, held together only by the tackiness of the uncuredrubber over the area of the adjacent ends. Metallic reinforcing cordsprovide a relatively linear calendered edge that is suitable for a buttsplice bond created by the tackiness of the elastomeric material.

[0005] However, if the elastomeric material has nonmetallic reinforcingcords, the lateral calendered edges of the material are not straight butundulating. Such curved calendered edges provide a nonuniform andvariable gap between the adjacent ends of the pieces and thus, aregenerally not considered suitable for a butt splice. Consequently,although a butt splice would be preferred in the manufacture of apreparation splice, an overlapping splice is often used to join the cutpieces having nonmetallic reinforcing cords.

[0006] Therefore, there is a need for improved apparatus and method forautomatically making a preparation ply with butt splices. Moreparticularly, there is a need for apparatus and methods forautomatically butt splicing together a preparation ply havingnonmetallic reinforcing cords.

SUMMARY OF THE INVENTION

[0007] In a first embodiment of the present invention, an apparatus isprovided that automatically butt splices a preparation ply havingmetallic or nonmetallic reinforcing cords. The apparatus is relativelysimple in design and less expensive than other machinery used to buttsplice a preparation ply. The apparatus of the present inventionprovides a high quality butt splice regardless of the reinforcing cordmaterial and therefore, is especially useful in making a preparation plyhaving nonmetallic reinforcing cords.

[0008] More specifically, the first embodiment of the invention providesan apparatus for forming a butt joint between ends of first and secondplies to splice the plies together. The apparatus has pairs of upperracks that extend end-to-end; and each pair of upper racks has first andsecond upper racks that are movable with respect to each other. Inaddition, pairs of lower racks extend end-to-end adjacent the pairs ofupper racks; and each pair of lower racks has first and second lowerracks that are movable with respect to each other. The first and secondlower racks support ends of first and second plies, respectively. Aclamp drive is connected to the pairs of upper racks and is operable tomove the upper racks toward the lower racks to clamp the ends of thefirst and second plies between the upper and lower racks. An engagementdrive is connected to the upper and lower racks and is operable tosimultaneously move all of the first and second racks with respect toeach other to firmly press the ends of the first and second pliestogether, thereby forming a butt joint splicing the ends of the firstand second plies together.

[0009] In another embodiment of this invention, a method is provided forpositioning an end of a first material ply section over teeth of thefirst lower racks and positioning an end of a second material plysection over teeth of the second lower racks. Next, the first and secondmaterial ply sections are clamped between the pairs of upper racks andthe pairs of lower racks. Then, the teeth of all the first upper andlower racks are simultaneously engaged with the teeth of all the secondupper and lower racks to firmly press the ends of the first and secondmaterial plies together to form a butt joint that splices the first andsecond material plies together.

[0010] In a second embodiment of the present invention, an apparatus isprovided that automatically applies a gum strip to a butt joint joiningtwo preparation plies together. The apparatus is fast, reliable andautomatically operable with the butt splicer described herein andtherefore, is especially useful in making a preparation ply havingnonmetallic reinforcing cords.

[0011] More specifically, the second embodiment of the inventionprovides an apparatus having a conveyor for providing a gum strip of adesired length. A transfer device then automatically removes the gumstrip from the conveyor and places the gum strip on the butt joint.

[0012] In a further embodiment of this invention, a method is providedfor applying a gum strip over a butt joint splicing ends of first andsecond preparation plies by first providing a gum strip having a desiredlength and then, automatically placing the gum strip on the butt joint.

[0013] In a third embodiment of the present invention, an apparatus isprovided that automatically forms a continuous preparation ply of thetype used to make vehicle tires from preparation ply sections havingnonmetallic cords. Being able to economically, efficiently and reliablybutt splice preparation plies provides a higher quality tiremanufacturing process.

[0014] More specifically, the second embodiment of the inventionprovides an apparatus having an infeed conveyor for successively feedingthe preparation ply sections, and a butt splicing machine that receivesthe preparation ply sections from the infeed conveyor. The butt splicingmachine joins the ends of the two preparation ply sections to form abutt joint splicing the two preparation plies together to form acontinuous preparation ply. An outfeed conveyor feeds the continuouspreparation ply from the butt splicing machine, and a gum strip applierapplies a gum strip on the butt joint of the continuous preparation plyon the outfeed conveyor.

[0015] In another embodiment of this invention, a method is provided forforming a continuous preparation ply by first automatically forming afirst butt joint splicing two preparation plies together to form acontinuous preparation ply having nonmetallic cords that extend in adirection substantially parallel to the butt joint. Thereafter, a gumstrip is automatically placed on the first butt joint.

[0016] These and other objects and advantages of the present inventionwill become more readily apparent during the following detaileddescription taken in conjunction with the drawings herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a schematic illustration of a nonmetallic cordpreparation ply manufacturing line having a butt splicer and gum stripapplier in accordance with the principles of the present invention.

[0018]FIG. 2 is a side view of the butt splicer and the gum stripapplier of FIG. 1.

[0019]FIG. 3 is a side view of the butt splicer of FIG. 2.

[0020]FIG. 4 is a partial perspective view of a portion of the buttsplicer of FIG. 2 that illustrates the plurality of pairs of upper andlower racks.

[0021]FIG. 5 is an end view of the butt splicer of FIG. 2.

[0022]FIGS. 6 and 6A are schematic block diagrams of a control systemused to control the operation of the butt splicer and gum strip applierof FIG. 1.

[0023]FIG. 7 is a flowchart of a subroutine implemented by the controlsystem of FIG. 6 for positioning a preparation ply piece prior to a buttsplicing cycle.

[0024] FIGS. 8-8C are end views illustrating different states of rackson the butt splicer of FIG. 1 in executing the butt splicing cycle ofFIG. 6.

[0025]FIG. 9 is a flowchart of a subroutine implemented by the controlsystem of FIG. 6 for butt splicing the preparation ply materials.

[0026]FIG. 10 illustrates how the upper pairs of racks are nonrigidlymounted in jaw mounting brackets on the butt splicer of FIG. 2.

[0027]FIG. 11 is an end view of the gum applier of FIG. 2.

[0028]FIG. 12 is a side view of the gum applier of FIG. 2.

[0029]FIG. 13 is a partial top view of the gum applier of FIG. 2illustrating the horizontal drive components.

[0030]FIG. 14 is a partial end view of the gum applier of FIG. 2illustrating the vertical drive components.

[0031]FIG. 15 is a flowchart of a subroutine implemented by the controlsystem of FIG. 6 for cutting a gum strip to length.

[0032]FIG. 16 is a flowchart of a subroutine implemented by the controlsystem of FIG. 6 for picking up the gum strip with the vacuum head.

[0033]FIG. 17 is a flowchart of a subroutine implemented by the controlsystem of FIG. 6 for applying the gum strip with the vacuum head.

[0034]FIG. 18 is a state diagram illustrating the operation of thecontrol system of FIG. 6 for simultaneously operating the butt splicerand gum strip applier of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

[0035] Referring to FIG. 1, in a preparation ply manufacturing line 20,a strip of calendered material 22 is fed from calender rolls (not shown)in a known manner. The calendered material 22 is about 0.040-0.060 inchthick and has cords 24 made from a nonmetallic material, which extendlongitudinally generally parallel to the calendered edges 26. Thenonmetallic cords 24 being less rigid than metallic cords result in thecalendered edges 26 being nonlinear and undulating. The calenderedmaterial is fed by a conveyor 28 past a cutter 30, which cuts thecalendered material to desired lengths, depending on the application.The resulting rectangular pieces 32 are then transferred onto atransverse infeed conveyor 34. The pieces are then conveyed in adownstream direction 35 to a butt splicing machine 36 that forms buttjoints 40 between the calendered edges 26 of the cut pieces 32 to form acontinuous preparation ply strip 38. The butt joints 40 are reinforcedby respective gum strips 42 that are placed over the joints 40 by a gumstrip applier 44. The resulting continuous preparation ply strip iscollected on windup rolls 43 in a known manner. The continuouspreparation ply strip 38 has nonmetallic cords 24 that are substantiallyparallel to the butt joints 40 and gum strips 42 and are transverse to alongitudinal axis 46 of the preparation ply strip 38.

[0036] For purposes of this description, the term “downstream” is usedto identify the direction of motion of the preparation ply material 38through the butt splicer 36 and gum strip applier 44, that is, fromright to left as viewed in FIG. 1. The term “upstream” is used todesignate a motion in an opposite direction. Components on the buttsplicer 36 that are identified as “downstream” are located closer to thegum strip applier 44 than components identified as being “upstream”.

[0037]FIG. 2 is a side view of a portion of the preparation plymanufacturing line 20, a strip of calendered material 22 that includesthe infeed conveyor 34, butt splicer 36 and gum strip applier 44. Itshould be noted that except for the butt splicer 36 and gum stripapplier 44, all of the elements of FIG. 1 are known and used in the tiremanufacturing industry. It should also be noted that preparationequipment 48 for the gum strip applier 44, which feeds the gum stripfrom a roll and separates and winds up a covering over the gum stripadhesive is also known.

[0038] Referring to FIGS. 4 and 5, the butt splicing machine 36 has aframe 72 that supports floating tables 70 on both the upstream anddownstream sides of the butt splicer 36. Pairs of upper racks 50 andpairs of lower racks 52 are mounted to extend transversely across thewidth of the butt splicing machine. Each pair of upper racks 50 iscomprised of a nonpivotable, upstream rack 54 having teeth 56 that areengageable with teeth 58 of a pivotable, downstream rack 60. Similarly,each pair of lower racks 52 is comprised of a nonpivotable, upstreamrack 62 having teeth 64 that are engageable with teeth 66 of apivotable, downstream rack 68. The pairs of lower racks 52 are fixed inelevation immediately adjacent the table 70 that supports the cut strips32 as they are fed by the infeed conveyor 34 to the butt splicer 36. Theracks 54, 60, 62, 68 are commercially available gear racks.

[0039] Each of the upper, upstream racks 54 is mounted to a lower end ofa respective upper, nonpivotable, upstream jaw mounting bracket 75 thatis mounted on a slide 76. The slide 76 is slidably mounted on a linearguide 77 that is fixed to an upper pair of cross rails 78 of the frame72. Each of the upper, downstream racks 60 is mounted to a lower end ofa respective upper, pivotable, downstream jaw mounting bracket 79. Upperends of each of the upper jaw mounting brackets 75, 79 are mechanicallyconnected to a clamp drive comprised of a respective upper clampingactuator 82, for example, a pneumatic cylinder, as shown in FIG. 5. Thecylinders 82 are mounted to a truss 95 that is mounted on gearboxes 97on the frame 72. The gearboxes 97 are connected by a shaft 99 andoperated by a handwheel 101. Thus, turning the handwheel 101 permits thevertical position of the cylinders 82 and the upper pairs of racks 50 tobe adjusted. The upper ends of each of the jaw mounting brackets 75, 79are pivotally connected via a pivot pin 80 to a distal end of a cylinderrod 81 of a respective cylinder 82. Simultaneous operation of thecylinders 82 in one state is operative to simultaneously move the upperjaw mounting brackets 75, 79 and respective pairs of upper racks 50downward toward the pairs of lower racks 52. Reversing the operation ofthe cylinders 82 is operative to move the upper racks 50 away from thelower racks 52.

[0040] As shown in FIG. 4, the upper, downstream racks 60 are pivotablewith respect to respective upper, upstream racks 54 by means of anengagement drive comprised of respective upper engagement actuators 83,for example, a pneumatic cylinder. Specifically, the cylinders 83 aremounted on respective upper, downstream jaw mounting brackets 79; and asshown in FIG. 3, distal ends of respective cylinder rods 85 areconnected to respective opposed, upper, upstream jaw mounting brackets75. Simultaneous operation of the engagement cylinders 83 in one statecauses the upper, downstream jaw mounting brackets 79 and respectiveupper, downstream racks 60 to pivot toward the upper, upstream jawmounting brackets 75 and the respective upper, upstream racks 54,thereby engaging their respective teeth 58, 56. Reversing the operationof the engagement cylinders 83 causes the upper, downstream racks 60 tomove simultaneously away from the upper rear racks 54, therebydisengaging their respective teeth 58, 56.

[0041] Each of the lower, upstream racks 62 is mounted to a lower end ofa respective lower, upstream, nonpivotable jaw mounting bracket 84 thatis attached to a lower pair of cross rails 87 fixed to the frame 72.Each of the lower, downstream racks 68 is mounted to a lower end of arespective lower, pivotable, downstream jaw mounting bracket 88. Upperends of each of the lower jaw mounting brackets 84, 88 are pivotallyconnected via a pivot pin 89. The lower, downstream racks 68 arepivotable with respect to respective lower, upstream racks 62 by meansof an engagement drive comprised of respective lower engagementactuators 90, for example, a pneumatic cylinder. Specifically, thecylinders 90 are mounted on respective lower, downstream jaw mountingbrackets 88; and as shown in FIG. 3, distal ends of respective cylinderrods 91 are connected to respective lower, upstream jaw mountingbrackets 84. Simultaneous operation of the engagement cylinders 90 inone state causes the lower, downstream jaw mounting brackets 88 andrespective lower, downstream racks 68 to pivot toward the lower,upstream jaw mounting brackets 84 and the respective lower, upstreamracks 62, thereby engaging their respective teeth 66, 64. Reversing theoperation of the engagement cylinders 90 causes the lower, downstreamracks 68 to move simultaneously away from the lower, upstream racks 62,thereby disengaging their respective teeth 66, 64.

[0042] Referring to FIG. 6, the operation of the floating table 70 andcylinders 90, 82, 83 are controlled by the operation of solenoids 94that port pressurized air from a source 96 in a known manner. Theoperational states of the solenoids are commanded by output signals froma control 98, for example, a programmable logic controller or othermicrocontroller. The operation of the control 98 is controlled by inputdevices, for example, a user I/O 100, an edge sensor 102, etc. Thecontrol 98 also provides output signals that command the operation of aninfeed conveyor motor 104 (FIG. 2) and an outfeed conveyor motor 106that operate the respective infeed and outfeed conveyors 34, 108.

[0043] The operation of the butt splicer 36 is controlled by variouscycles of operation that are programmed in the control 98 in a knownmanner as a group of subroutines. For example, a first subroutineillustrated in FIG. 7 is effective to position cut pieces 32 in the buttsplicer 36 in preparation for making the butt joint. The process of FIG.5 starts with a preparation ply in the butt splicer 36 and a butt jointhas just been completed. Referring to FIGS. 1, 2, 6 and 7, to positionthe preparation ply 38 and a new cut piece 32 for the next splice, thecontrol 98 provides, at 502, output signals to cause the infeed andoutfeed conveyor motors 104, 106, respectively, to run. At the sametime, the control 98 provides an output signal to solenoid 94d causingit to switch state and port pressurized air to the floating tables 70.Thus, material can be moved over the butt splicer 36 with minimalfriction from a subjacent support. Simultaneous operation of the infeedand outfeed conveyors 34, 108 causes the preparation ply strip 38 tomove in a downstream direction 35 as viewed in FIGS. 1, 2 and 8. Thatmotion of the preparation ply strip 38 results in a trailing edge 110(FIG. 8) passing beneath an edge sensor 102 mounted on the butt splicer36. Upon detecting the trailing edge 110, the edge sensor 102 providesan output signal, at 504, to the control 98.

[0044] The control 98 then monitors the operation of the outfeedconveyor 108 to determine when the trailing edge 110 has been moved to adesired position with respect to the teeth 66 of the lower, downstreamrack 68. The distance between the point at which the trailing edge 110is sensed by the edge sensor 102 and the final position of the trailingedge 110 on the lower, downstream rack 68 is a known value. Therefore,the operation of the outfeed conveyor motor 106 can be preciselycontrolled such that the outfeed conveyor 108 is stopped when thetrailing edge 110 is at its desired position on the lower, downstreamrack 68. The desired position of the trailing edge varies depending onthe design of the butt splicer 36, the depth of the teeth of the racks,the nature of the preparation ply material, etc. The desired position ofthe trailing edge 110 is back from the front edges of the teeth 66 ofthe lower, downstream rack 68. However, the desired amount of setback ofthe trailing edge 110 is determined experimentally in each applicationand may, for example, be a distance equal to somewhat less than half thelength of the teeth 66.

[0045] Detecting when the trailing edge 110 is in position may beaccomplished in several ways. In one embodiment, the outfeed conveyormotor 106 has an encoder 112 attached thereto; and each output pulsefrom the encoder represents an incremental displacement of the outfeedconveyor 108. Thus, the control 98 can detect and count output pulsesfrom the encoder 112 and detect, at 506, when the trailing edge 110 isat its desired position on the teeth 66 of the lower, downstream rack68. In an alternative embodiment, if the speed of the outfeed conveyor108 is fixed, the control 98 can start an internal timer that counts themilliseconds required to move the trailing edge 110 from its positionunder the edge sensor 102 to a desired position on the teeth 66 of thelower, downstream rack 68. In either event, when the control 98determines, at 506, that the trailing edge is at its desired position,it provides, at 508, an output signal to the outfeed conveyor motor 106commanding it to stop. In addition, the control 98 provides an outputsignal switching the state of solenoid 94 d to remove the supply ofpressurized air from the downstream floating table 70, thereby providinga more rigid support for the cut piece 38.

[0046] Simultaneously, with moving of the preparation ply 38, theoperation of the infeed conveyor 34 by the control 98 is also causing anew cut piece 32 to move in the downstream direction 35 toward the buttsplicer 36. After detecting the trailing edge 110 of the preparation ply38, the edge sensor 102 detects the leading edge 114 of the next cutpiece 32 to be spliced to the preparation ply strip 38; and its outputchanges state at 510. Upon the control 98 detecting that change ofstate, it starts counting pulses from an encoder 116 that is connectedto the infeed conveyor motor 104. By counting encoder pulses, thecontrol 98 is able to determine when the leading edge 114 is at adesired position on the teeth 64 of the lower, upstream rack 62. Again,the desired position of the leading edge 114 varies depending on thedesign of the butt splicer 36, the depth of the teeth of the racks, thenature of the preparation ply material, etc. The desired position of theleading edge 114 is determined in the same way as described with respectto the desired position of the trailing edge 110. Upon the control 98detecting, at 512, the desired position of the leading edge 114, itprovides, at 514, an output signal to the infeed conveyor motor 104commanding it to stop. It should be noted that the infeed conveyor 34and outfeed conveyor 108 normally have about equal speeds, however, theoutfeed conveyor may be run slightly faster than the infeed conveyor toincrease the gap between the trailing edge 110 of the preparation ply 38and the leading edge of the ply section 32 during conveyance.

[0047] In addition, the control 98 provides an output signal switchingthe state of solenoid 94 d to remove the supply of pressurized air fromthe upstream floating table 70, thereby providing a more rigid supportfor the cut piece 32. At this point, the edges 110, 114 are at desiredlocations on respective teeth 66, 64 of the lower rear and forward racks68, 62, respectively.

[0048] After the edges are at the desired locations, the butt splicer isready to form a butt splice joining the preparation ply strip 38 withthe new cut piece 32. Referring to FIG. 9, a process for making a buttsplice begins with the control 98 providing, at 516, an output signal tothe solenoid 94 a causing the solenoid to switch states and portpressurized air to the clamp cylinders 82. The clamp cylinderssimultaneously lower the plurality of upper racks 50 until the upper,downstream racks 60 contact a portion of the preparation ply strip 39adjacent the trailing edge 110 being supported by respective lower,downstream racks 68. At about the same time, the upper, upstream racks54 contact a portion of the cut strip 32 adjacent the leading edge 114being supported by the lower, upstream racks 62 as shown in FIG. 8A. Thetime required to move the upper racks to their clamped position can bemeasured, and the control 98 can be programmed to initiate an internaltimer equal to that clamping operation time. Therefore, when that timerexpires, the control 98 then determines, at 518, that the upper pairs ofracks 50 have been moved to their respective desired clamped positions.

[0049] Thereafter, the control 98 then provides, at 520, output signalsto solenoids 94 b, 94 c to change the states of those solenoids and portpressurized air into the upper and lower engagement cylinders 83, 90,respectively. The engagement cylinders 83, 90 are effective to move theupper and lower, downstream racks 60, 68 toward their mating upper andlower, upstream racks 54, 62. The clamped upper and lower, downstreamracks 60, 68 move the preparation ply 38 in an upstream direction 117(FIG. 8A) to bring the preparation ply strip trailing edge 110 intocontact with the cut piece leading edge 114 in an abutting relationship.Continued motion of the upper and lower, downstream racks 60, 68 firmlyforces the preparation ply strip trailing edge 110 against the cut pieceleading edge 114 to form the butt splice 40 (FIG. 8B). The tackiness ofthe elastomeric material helps to maintain the cut piece leading edge114 in intimate contact with the preparation ply strip trailing edge110. That motion continues until the teeth 58, 66 of the respectiveupper and lower, downstream racks 60, 68 are fully engaged with theteeth 56, 64 of the respective upper and lower, upstream racks 54, 62 asshown in FIG. 8B.

[0050] Once again, as previously described, the control 98 is able, bymeans of an internal timer, to determine, at 522, that the upper andlower, downstream racks 60, 68 are fully engaged with respective upperand lower, upstream racks 54, 62. At that point, the control 98provides, at 524, an output signal to switch the state of solenoid 94 a,thereby reversing the porting of pressurized air to the clamp cylinders82. The actuation of the clamp cylinders 82 causes the pairs of upperracks 50 to be raised and moved back to their unclamped position asshown in FIG. 8C. Immediately thereafter, the control 98 provides, at526, output signals to the solenoids 94 b, 94 c to switch the states ofthe upper and lower engagement cylinders 83, 90, thereby moving theupper and lower, downstream racks 60, 68 in the downstream direction 35away from the upper and lower, upstream racks 54, 62. That operationcauses the racks to open to a position illustrated in FIG. 8.

[0051] In the above process, it should be noted that as the upper andlower, downstream racks 60, 68 move toward the respective upstream racks54, 62, the downstream racks 60, 68 and the preparation ply 38 movesimultaneously. However, after the preparation ply trailing edge 110contacts the cut piece leading edge 114, the upper and lower, downstreamracks 60, 68 have a relative motion with respect to the preparation plystrip 38 and therefore, must slide over the major surfaces of thepreparation ply strip 38 without causing damage. To facilitate this, thesides 93 of the pivoting, downstream racks 60, 68 are coated with a“TEFLON” material. In addition, the teeth of the upper and lower,downstream racks 60, 68 are beveled at their leading edge of contact,that is, the surface 92 (FIG. 4). The exact configuration of a beveledsurface 92 is application dependent and varies with the nature of theply material, the length of the racks, etc. In some applications, thebeveled surface 92 has an angle of about 10° with respect to the sidesurface 93 of the rack; whereas, in other applications, the beveledsurface has an angle of about 20°. The angle providing the bestperformance is determined experimentally by trial and error. Similarly,the desired length of the beveled surface 92 and its desired depth fromthe side surface 93 is also determined experimentally by trial anderror. Such a beveled surface 92 facilitates a sliding motion of thedownstream racks 60, 68 over the preparation ply strip 38 withoutgouging it or otherwise causing damage.

[0052] In operating the butt splicer 36, it has been found that having aplurality of pairs of upper and lower racks 50, 52 provides a moreconsistent, higher quality butt splice than if the upper and lower racks50, 52 extended continuously across a full width of the butt splicer 36.The reliability and quality of the butt splice is further improved bynonrigidly mounting the upper racks 54, 60 to respective upper jawmounting brackets 75, 79. The nonrigid mountings of the racks 54, 60 areidentical; and the mounting of rack 54 onto jaw mounting bracket 75 isshown in FIG. 10. Shoulder bolts 122 have shoulders that extend throughslots 123 in the jaw mounting bracket 75 and threadedly engage the rack54. Thus, the rack 54 is not rigidly mounted to the respective jawmounting bracket but is free to move relative thereto by an amountdepending on the size of the slots 123. Further, the end of the jawmounting bracket 75 has a generally L-shaped notch 124 extending acrossa width of the jaw mounting bracket 75. The slots 123 intersect a firstnotch surface 125 that contacts a rear surface of the rack 54. Aperpendicular surface 126 of the notch is curved, for example, with a 30inch radius, to allow the rack 54 to rock thereon. It has beendetermined that such nonrigidly mounting of the upper racks 54, 60 torespective jaw mounting brackets 75, 79 substantially improves thequality of the butt splice 40.

[0053] The operation of the butt splicer 36 is effective to providereliable and high quality butt joints in the formation of a preparationply strip. Further, it should be noted that the butt splicer 36 can beused to form butt splices that are substantially perpendicular to theinfeed conveyor 34 as well as butt splices that are oblique with, orangled slightly from a perpendicular to the infeed conveyor 34.Referring to FIG. 3, a forward leg 131 of the frame 72 of the buttsplicer 36 is pivotally mounted to a base plate 132. A rearward leg (notshown) of the frame 72 is supported by a caster 133 that rides on thebase plate 132. A ballscrew and nut assembly 134 is connected betweenthe rearward leg and a handwheel 135. Turning the handwheel 135 rotatesthe ballscrew and causes the nut that is pivotally attached to therearward leg of the frame 72 to travel along the ball screw. As the nutis moved, the rearward leg of the frame 72 pivots with respect to theforward leg 131, thereby skewing the rows of upper and lower racks 50,52 with respect to a line perpendicular to a longitudinal centerline ofthe infeed conveyor 34. An indicator associated with the handwheel 135is calibrated in one degree increments. Permitting the frame 72 to bepivoted through an angle of up to about 10 degrees is sufficient formost applications.

[0054] It has been found that for preparation ply strips made withnonmetallic cords, the butt joint is stronger and more stable during thetire manufacturing process if it is covered with a gum strip. For themost efficient operation, the gum strip applier 44 operatessimultaneously with the butt slicer 36. Therefore, the gum strip applier44 is positioned with respect to the butt splicer 36 such that,simultaneously with the preparation ply trailing edge being positionedat the butt splicer 36, the most recently formed butt splice ispositioned at a location at which a gum strip can be applied by the gumstrip applier 44.

[0055] Referring to FIG. 11, outfeed conveyor 108 is supported by a base126. The gum strip applier 44 has a frame 127 that is independentlysupported by a base 128 having legs 129. Thus, the outfeed conveyor 108and gum strip applier 44 are independently positionable with respect tothe butt splicer 36. The gum strip applier 44 is positioned such thatwhen a butt splice is being formed on the butt splicer 36, a previouslymade butt splice is located on outfeed conveyor 108 at a location 140permitting the gum strip applier 44 to apply a gum strip to thepreviously made butt splice. Referring to FIG. 12, the gum strip applier44 has a gum strip conveyor 142 and a vacuum head assembly 144. Thevacuum head assembly 144 has two degrees of freedom that permit it toremove a gum strip from the conveyor 142 and place it on a butt splicepositioned at the upstream location 140.

[0056] Referring to FIG. 13, an X-axis, horizontal drive motor 146 ismechanically connected to one end of a ball screw 148; and a sprocket150 is mounted on an opposite end of the ball screw 148 and operativelyengages a timing belt 152. The timing belt 152 is further connected to asecond sprocket 154 mounted on an end of a second ball screw 156. Theball screws 148, 156 have respective ball nuts 158, 160 that support andcarry a carriage 162 that is supported and guided in its linear motionby linear bearings 163. As shown in FIG. 13, the carriage 162 supportsthe vacuum head assembly 144. The vacuum head assembly 144 has a lengthsubstantially equal to the length of the butt splice, that is, the fullwidth of the preparation ply strip. Rotation of the horizontal drivemotor 146 is operative to simultaneously move the ball nuts 158, 160(FIG. 13), the carriage 162 and the vacuum head assembly 144 in ahorizontal direction substantially parallel to a longitudinal axis ofthe preparation ply strip.

[0057] Referring to FIG. 14, a Z-axis vertical drive motor 164 ismounted on, and supported by, the carriage 162 and is mechanicallyconnected to one end of a first ball screw 166. A first timing sprocket168 is mounted on an opposite end of the first ball screw 166 andoperatively engages a timing belt 170 that also engages a sprocket 172mounted on an end of a second ball screw 174. First and second ball nuts176, 178 are rotatably mounted on the respective ball screws 166, 178and are connected to a vacuum head plenum 180, which is guided in itslinear motion by linear bearings 181.

[0058] Referring to FIG. 12, a vacuum head 182 is supported by verticalposts 184 that are fixed to the plenum 180. Biasing components, forexample, compression springs 181, are mounted on the posts 184 betweenthe vacuum head 182 and the plenum 180. The vacuum head 182 has a lengththat extends across substantially the whole width of the outfeedconveyor as well as the length of a butt splice in the preparation plystrip. Thus, operation of the vertical drive motor 164 causes the vacuumplenum 180 and vacuum head 182 to raise and lower with respect to theoutfeed conveyor 108.

[0059] Referring to FIG. 6B, the control 98 provides output signals tothe strip conveyor motor 186 and receives input pulses from a stripconveyor encoder 188 by which the control 98 can determine the linearmotion of the strip conveyor 142. Similarly, in response to outputsignals commanding the operation of the horizontal and vertical drivemotors 146, 164, the control 98 receives feedback signals from theencoders 190, 192 representing motion of the vacuum head 182. Thecontrol 98 is also operatively connected to a vacuum pump 194 thatapplies the partial vacuum pressure to the vacuum head plenum 180. Avacuum is applied and released from the vacuum head 182 by means of avacuum release valve 196 connected between the vacuum head plenum andthe vacuum head 182. When in its first state, the valve 196 closes thevacuum head to atmosphere and opens it to the vacuum head plenum 180,thereby applying a partial vacuum to the vacuum head 182. In itsopposite state, the valve 196 closes the connection between the vacuumhead 182 and the vacuum head plenum 180 and opens the vacuum head 182 toatmosphere, thereby dissipating the partial vacuum therein. The control98 is also connected to a solenoid 94 e that is operative to change thestate of a knife cylinder 198, thereby operating a knife 200 on the gumstrip preparation equipment 48 (FIG. 2) for cutting the gum strips todesired lengths.

[0060] There are three independent but coordinated operations orsubroutines that are executed by the gum strip applier 44. Referring toFIG. 12, first, a gum strip 42 is moved by the conveyor 142 to alocation ready for transfer to the vacuum head 182. A second operationis for the vacuum head 182 to pick up the gum strip from the conveyor142 and be ready to apply the gum strip to the butt joint. A thirdoperation is to apply the gum strip to the butt joint after the buttjoint has been moved to the desired location 140 (FIG. 11). Referring toFIGS. 6B, 12 and 15, to cut a gum strip to length, the control 98provides, at 552, an output signal to operate the strip conveyor motor186, thereby causing the strip conveyor 142 to feed the gum strip. Asthe gum strip 42 is fed, the control 98 monitors and counts outputpulses from the strip conveyor encoder 188. When the control 98 counts,at 554, a number of pulses equal to the desired length of the gum strip,the control 98 provides, at 556, an output signal commanding the stripconveyor motor 186 to stop. Thereafter, the control 98 provides, at 558,an output signal commanding the solenoid 94e to change state, therebyporting pressurized fluid to the knife cylinder 198 and operating theknife 200. Immediately thereafter, the output signal from the control 98changes state, thereby reversing the state of solenoid 94 e andreturning the knife cylinder 198 to its original position. Thatoperation of actuating the knife cylinder reciprocates the knife 200 andestablishes a cut end of the gum strip 145. This action provides a gumstrip on the strip conveyor 142 that is of the desired length, that is,the length of the butt strip 40.

[0061] Thereafter, the control 98 provides, at 560, an output signalcommanding the strip conveyor motor 186 to start; and the strip conveyor142 transports the gum strip 42 across the width of the outfeed conveyor108. Again, the control 98 is monitoring and counting output pulses fromthe strip conveyor encoder 188 and is able to determine when the cut gumstrip is in its desired position. When that position is detected, at562, the control 98 provides, at 564, an output signal commanding thestrip conveyor motor 186 to stop. At this point, a gum strip 42 of thedesired length is located on the strip conveyor 142 at a location readyto be picked up by the vacuum head 182.

[0062] Referring to FIGS. 6B, 11 and 16, to pick up the gum strip fromthe gum strip conveyor 142, assume that the vacuum head 182 is elevatedand the carriage 162 is positioned to locate the vacuum head 182 at adownstream location above the gum strip conveyor 142, ready to pick up agum strip. The control 98 provides, at 565, an output signal to thevacuum release valve 196 closing the vacuum head 182 to atmosphere andopening the vacuum head to the vacuum head plenum 180. A vacuum is thenapplied to the vacuum head 182. The control 98 also provides, at 565,output signals to the Z-axis, vertical drive motor 164, thereby rotatingthe ball screws 166, 174 in a direction to move the vacuum head 182vertically downward toward the gum strip conveyor 142. The controlmonitors and counts output pulses from the vertical drive encoder 192and detects, at 566, when the vacuum head 182 is at its desired positionimmediately above the strip conveyor 142. At that position, the vacuumhead 182 is sufficiently close to the strip conveyor 142 that the vacuumhead 182 is able to lift the gum strip off of the gum strip conveyor142.

[0063] The control 98 then provides, at 567, output signals to theZ-axis vertical drive motor 164 and the X-axis horizontal drive motor146 causing the vacuum head to move to a ready position immediatelyabove the location 140 at which the butt joint is located. As will beappreciated, the control 98 can be programmed to first operate thevertical drive motor 164 to raise the vacuum head 182 and thereafter,operate the horizontal drive motor 146 to move the vacuum headhorizontally to a ready position over the butt joint location 140.Alternatively, in other applications, the motors 146 and 164 can beoperated simultaneously to move the vacuum head 182 to the readyposition. In either embodiment, the control signal monitors outputpulses from the encoders 190, 192 in a manner previously described todetect, at 568, that the vacuum head 182 is at the ready position.Thereafter, the control 98 provides, at 569, output signals to theeither or both of the motors 146, 164 commanding them to stop the vacuumhead 182 at the ready position.

[0064] Referring to FIGS. 6B, 11, 12 and 17, to apply the gum strip tothe butt joint, assume that a butt joint has been moved to the location140 beneath the vacuum head 182 at the ready position. The control 98provides, at 572, output signals to the Z-axis, vertical drive motor 166rotating ball screws 166, 174 in a direction causing the vacuum head 182to lower onto and contact the preparation ply strip 38. The gum striphas a length that extends over substantially the whole length of thebutt splice. Further, the gum strip has a width such that it extendsacross the butt splice and over a portion of the major surfaces on bothsides of the butt splice 40. The vacuum head 182 is resiliently andmovably mounted with respect to the vacuum head plenum 180. Therefore,as the vertical drive motor 164 continues to move the vacuum head plenum182 downward, the vacuum head 182 contacts the preparation ply strip 38and the springs 181 apply a desired, downward biasing force against thevacuum head 182, thereby applying a desired application force againstthe gum strip 42. That force is determined by spring constants ofsprings 181 and is effective to cause the adhesive on the gum strip 42to better adhere to the preparation ply strip 38.

[0065] Again, the control 98 is monitoring the output pulses from theencoder 190 and detects, at 573, when the vacuum head 182 has been movedto its lowermost position. Thereafter, the control 98 provides, at 574,an output signal to the vertical drive motor 164 commanding it to stop.In addition, the control 98 provides an output signal to the vacuumrelease valve 196 changing the state of the valve such that the fluidconnection between the vacuum head plenum and the vacuum head 182 isblocked, and the vacuum head 182 is open to atmosphere. At this point,the control 98 may allow the vacuum head 182 to dwell at its lowermostposition to allow the adhesive on the gum strip to set. Such a dwelltime is determined by an internal timer in the control 98 and can be setfrom zero to any desired number of seconds in a known manner.

[0066] Thereafter, the control 98 provides, at 575, output signalscommanding the drive motor 146, 162 to move the vacuum head back to thepickup position above the gum strip conveyor 142. In a manner aspreviously described, the control monitors the encoders 190, 192 todetect, at 576, when the vacuum head 182 is at the pickup position; andthereafter, at 577, the control 98 provides output signals to stop thedrive motors 146, 164.

[0067] As indicated earlier, it is desirable that the gum strip applier44 operate simultaneously with the butt splicer 36 to apply the gumstrip 42 over the most recently formed butt splice while the buttsplicer 36 is splicing the next cut piece 32 to the preparation plystrip 38. Therefore, prior to a splice being moved to the position 140,the gum strip applier 44 is operated to prepare a gum strip forapplication. From the above, it is clear that for a more efficientoperation, several of the above processes and subroutines can beoperating simultaneously. For example, while a butt splice is being made(FIG. 9) and a gum strip is being applied over a previously made buttsplice (FIG. 17), a gum strip can be cut to size and moved into the gumstrip applier (FIGS. 15 and 16). FIG. 18 is a state diagram of a programin the control 98 that permits several operations or subroutines to beoperated simultaneously.

[0068] If at 580, there is no gum strip on the gum strip conveyor 142,the control 98 executes, at 581, the subroutine of FIG. 15 to cut a gumstrip to length. If a gum strip is on the conveyor 142, the control 98determines, at 582, whether the vacuum head is empty; and if so,executes, at 583, the subroutine of FIG. 16 to pick up a gum strip fromthe conveyor 142. If the vacuum head 182 is holding a gum strip, thecontrol, at 584, determines whether a butt splice is in position andready to be made. If so, the control, at 585, 586, proceeds to make abutt splice by executing the butt splice subroutine of FIG. 9 andsimultaneously apply gum strip to a previously made butt splice byexecuting the subroutine of FIG. 17. If the control 98, at any time,detects, at 584, that a butt splice is not in position ready to be made,it brings a new cut piece 32 into the butt splicer 36 by executing theposition preparation ply subroutine of FIG. 7. The above processprovides an economical, efficient and reliable butt splice ofpreparation plies, thereby providing a higher quality tire manufacturingprocess.

[0069] It should be noted that the location of the gum strip applier 44can be adjusted with respect to the butt splicer 36 to accommodatedifferent widths of calendered material being supplied to the infeedconveyor 34.

[0070] Referring to FIG. 12, each side of the gum strip applier frame127 has grooved rollers 136 that are mounted on opposite sides of alinear guide 137 attached to the base 128. As shown in FIG. 11, aballscrew and nut assembly 138 is mounted to the base 128. A handwheel139 is operatively connected to the ballscrew nut and is rotatablymounted to the frame 127. Rotation of the handwheel 139 rotates theballscrew nut causing it to move the frame 127 and the componentssupported thereby with respect to the base 128 and the butt splicer 36.Thus, calendered material of different widths can be readilyaccommodated. It should be noted that when the location of the frame 127and gum strip conveyor 142 is changed, the feeding of the gum strip 42from the preparation equipment 48 (FIG. 2) must also be adjusted in aknown manner, for example, by moving the location of the equipment 48.

[0071] While the present invention has been illustrated by a descriptionof various embodiments and while these embodiments have been describedin considerable detail, it is not the intention of Applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. For example, in the described embodiment, theengagement actuators 85, 90 and clamping actuator 82 are described asbeing pneumatic cylinders; as will be appreciated, in alternativeembodiments, those actuators may be hydraulic actuators orelectromechanical drive systems.

[0072] In the described embodiment, individual clamping cylinders 82 areused for each upper pair of racks 50; however, in an alternativeembodiment, all of the pivotable jaw mounting brackets 79, 88 can bemechanically connected to a common drive link that is operated by onlyone or two actuators. In another alternative embodiment, all of theupper, pivotable jaw mounting brackets 79 can be mechanically connectedto a common drive link that is operated by only one or two actuators;and all of the lower, pivotable jaw mounting brackets 88 can bemechanically connected to another common drive link that is operated byonly one or two actuators. In the described embodiment, the upper pairsof racks are movable vertically and the lower pairs of racks 52 arefixed in elevation. In alternative embodiments, that arrangement can bereversed with the upper pairs of racks being fixed and the lower pairsof racks being movable.

[0073] Further, in the described embodiment, the upper and lower pairsof racks are mounted on the downstream side of the frame 72. Thus, thepivoting racks 60,68 are located downstream of the nonpivoting racks 54,62; however, in an alternative embodiment, the upper and lower pairs ofracks 50, 52 can be mounted on the opposite, upstream side of the frame72. In that embodiment, the pivoting racks 60, 68 are located upstreamof the nonpivoting racks 54, 62; and the nonpivoting racks 54, 62 holdthe preparation ply 38, while the pivoting racks 60, 68 pull the cutpiece 32 toward the preparation ply 38 to form the butt splice.

[0074] In the described embodiment, the control 98 is depicted as asingle unit; however, as will be appreciated, the control 98 can becomprised of several different control units that are in electricalcommunications with each other. Further, such different control unitsare often in different locations. For example, one control unit may beplaced with the butt splicer 36, another with the gum strip applier 44and a third with the preparation equipment 48.

[0075] Therefore, the invention in its broadest aspects is not limitedto the specific details shown and described. Consequently, departuresmay be made from the details described herein without departing from thespirit and scope of the claims which follow.

What is claimed is:
 1. An apparatus for forming a butt joint betweenends of first and second plies to splice the first and second pliestogether comprising: pairs of upper racks extending end-to-end, each ofthe pairs of upper racks having first and second upper racks movablewith respect to each other; pairs of lower racks extending end-to-endadjacent the pairs of upper racks, each of the pairs of lower rackshaving first and second lower racks movable with respect to each other,the first and second lower racks adapted to support ends of the firstand second plies, respectively; a clamp drive operatively connected tothe pairs of upper racks and being operable to move the pairs of upperracks toward the pairs of lower racks to clamp the ends of the first andsecond plies between the pairs of upper racks and the pairs of lowerracks; and an engagement drive operatively connected to the pairs ofupper racks and the pairs of lower racks and being operable tosimultaneously move all first and second racks with respect to eachother to firmly press the ends of the first and second plies togetherand form a butt joint splicing the ends of the first and second pliestogether.
 2. The apparatus of claim 1 wherein the engagement drivefurther comprises: a first engagement drive operatively connected to thepairs of upper racks; and a second engagement drive connected to thepairs of lower racks.
 3. The apparatus of claim 1 wherein the engagementdrive further comprises: upper engagement actuators, each engagementactuator operatively connected to a different one of the pairs of upperracks; and lower engagement actuators, each of the lower engagementactuators operatively connected to a different one of the pairs of lowerracks.
 4. The apparatus of claim 1 wherein the clamp drive furthercomprises clamp actuators, each of the clamp actuators operativelyconnected to a different one of the pairs of upper racks.
 5. Theapparatus of claim 1 further comprising: upper mounting brackets, eachof the upper racks being mounted in, and movable with respect to, adifferent one of the upper mounting brackets; and lower mountingbrackets, each of the lower racks being mounted in a different one ofthe lower mounting brackets.
 6. The apparatus of claim 5 wherein theupper mounting brackets comprise pairs of upper mounting brackets, eachpair of upper mounting brackets having a first upper mounting bracketsupporting a first upper rack and being movable with respect to a secondupper mounting bracket supporting a second upper rack; and the lowermounting brackets comprise pairs of lower mounting brackets, each pairof lower mounting brackets having a first lower mounting bracketsupporting a first lower rack and being movable with respect to a secondlower mounting bracket supporting a second lower rack.
 7. The apparatusof claim 6 wherein the first upper mounting bracket is nonpivotable, andthe second upper mounting bracket is pivotable with respect to the firstupper mounting bracket; and the first lower mounting bracket isnonpivotable, and the second lower mounting bracket is pivotable withrespect to the first lower mounting bracket.
 8. The apparatus of claim 7wherein the first and second plies of material are movable in adirection of motion and wherein further the second upper mountingbracket is located downstream of the first upper mounting bracket, andthe second lower mounting bracket is located downstream of the firstlower mounting bracket.
 9. The apparatus of claim 8 wherein the firstupper racks and the first lower racks have respective first sets ofteeth and the second upper racks and the second lower racks haverespective second sets of teeth, the first sets of teeth being locatedopposite to, and engageable with, the second sets of teeth.
 10. Theapparatus of claim 9 wherein each of the upper and lower racks has aside surface adapted to contact a major surface of a ply, and the sidesurface has respective bevel surfaces to facilitate the side surfacesliding over the major surface of the ply without damage thereto.
 11. Anapparatus for forming a butt joint between ends of first and secondplies to splice the first and second plies together comprising: pairs ofupper racks having teeth and extending end-to-end, each of the pairs ofupper racks having first and second upper racks movable with respect toeach other; pairs of lower racks having teeth and extending end-to-endadjacent the pairs of upper racks, each of the pairs of lower rackshaving first and second lower racks movable with respect to each other,the first and second lower racks adapted to support ends of the firstand second plies, respectively; a clamp drive operatively connected tothe pairs of upper racks; an engagement drive operatively connected tothe pairs of upper racks and the pairs of lower racks; and a controlconnected to the clamp and engagement drives and being operable to firstcommand the clamp drive to move the pairs of upper racks toward thepairs of lower racks and clamp the ends of the first and second pliesbetween the pairs of upper racks and the pairs of lower racks, andthereafter command the engagement drive to simultaneously move all firstand second racks with respect to each other to engage the teeth of thefirst and second racks and firmly press the ends of the first and secondplies together, thereby forming a butt joint splicing the ends of thefirst and second plies together.
 12. An apparatus for forming a buttjoint between ends of first and second plies to splice the first andsecond plies together comprising: pairs of upper racks extendingend-to-end, each of the pairs of upper racks having first and secondupper racks movable with respect to each other; pairs of lower racksextending end-to-end adjacent the pairs of upper racks, each of thepairs of lower racks having first and second lower racks movable withrespect to each other, the first and second lower racks adapted tosupport ends of the first and second plies, respectively; a clamp driveoperatively connected to pairs of one of the upper racks and the lowerracks and being operable to move the pairs of the one of the upper racksand the lower racks toward pairs of an other of the upper racks and thelower racks to clamp the ends of the first and second plies between thepairs of upper racks and the pairs of lower racks; and an engagementdrive operatively connected to the pairs of upper racks and the pairs oflower racks and being operable to simultaneously move all first andsecond racks with respect to each other to firmly press the ends of thefirst and second plies together and form a butt joint splicing the endsof the first and second plies together.
 13. A method for forming a buttjoint between ends of first and second plies to splice the first andsecond plies together comprising: providing pairs of upper racksextending end-to-end having first upper racks movable with respect tosecond upper racks; providing pairs of lower racks extending end-to-endadjacent the pairs of upper racks, the pairs of lower racks having firstlower racks movable with respect to second lower racks; positioning anend of a first ply on the first lower racks; positioning an end of asecond ply on the second lower racks; clamping the first and secondplies between the pairs of upper racks and the pairs of lower racks;automatically engaging the first upper racks with the second upper racksand the first lower racks with the second lower racks to firmly pressthe end of the first ply against the end of the second ply to splice thefirst and second plies together.
 14. The method of claim 13 furthercomprising automatically substantially simultaneously engaging all firstupper racks with all second upper racks, and all first lower racks withall second lower racks.
 15. The method of claim 13 further comprising:unclamping the first and second plies from between the plurality ofpairs of upper and lower racks; and disengaging the first upper racksfrom second upper racks and the first lower racks from the second lowerracks.
 16. A method of forming a continuous material ply of the typeused to make vehicle tires, the continuous material ply being made byjoining material ply sections, the method comprising: providing pairs ofupper racks having teeth and extending end-to-end having first upperracks movable with respect to second upper racks; providing pairs oflower racks having teeth and extending end-to-end adjacent the pairs ofupper racks, the pairs of lower racks having first lower racks movablewith respect to second lower racks; positioning an end of a firstmaterial ply section over teeth of the first lower racks; positioning anend of a second material ply section over teeth of the second lowerracks; clamping the first and second material ply sections between thepairs of upper racks and the pairs of lower racks; simultaneouslyengaging teeth of all first upper racks with teeth of all second upperracks, and teeth of all first lower racks with teeth of all second lowerracks to firmly press the end of the first material ply against the endof the second material ply to splice the first and second material pliestogether.
 17. An apparatus for applying a gum strip over a butt jointsplicing ends of first and second preparation plies together comprising:a conveyor for providing a gum strip having a desired length; and atransfer device for automatically removing the gum strip from theconveyor and placing the gum strip on the butt joint.
 18. The apparatusof claim 17 wherein the transfer device comprises a vacuum head.
 19. Theapparatus of claim 18 wherein the vacuum head is resiliently mounted tothe transfer device to provide a force against the gum strip upon thegum strip being placed on the butt joint.
 20. The apparatus of claim 17further comprising a cutting apparatus for automatically cutting the gumstrip to the desired length.
 21. The apparatus of claim 17 furthercomprising a control operatively connected to the conveyor and thetransfer device to operate the conveyor and the transfer device.
 22. Anapparatus for applying a gum strip over a butt joint splicing ends offirst and second preparation plies together comprising: a conveyor forsupporting a gum strip; a first drive mounted above the conveyor andproviding motion in a first direction; a second drive mounted to thefirst drive and providing motion in a second direction substantiallyperpendicular to the first direction; a vacuum head mounted to thesecond drive; and a control connected to the conveyor and the first andsecond drives and operable to first command the conveyor to move the gumstrip to a location adjacent a butt joint and thereafter command thefirst and second drives to move the vacuum head in the first and seconddirections to remove the gum strip from the conveyor and place the gumstrip on the butt joint.
 23. The apparatus of claim 22 wherein the firstdirection is a substantially horizontal direction and the seconddirection is a substantially vertical direction.
 24. A method forapplying a gum strip over a butt joint splicing ends of first and secondpreparation plies together comprising: providing a gum strip having adesired length; and automatically placing the gum strip on the buttjoint.
 25. The method of claim 24 further comprising: prior toautomatically placing the gum strip on the butt joint, automaticallylifting the gum strip from a conveyor; and after automatically placingthe gum strip on the butt joint, automatically pressing the gum stripagainst the butt joint.
 26. An apparatus for forming a continuouspreparation ply of the type used to make vehicle tires, the continuouspreparation ply being made from preparation ply sections havingnonmetallic cords, the apparatus comprising: an infeed conveyor forsuccessively feeding the preparation ply sections; a butt splicingmachine for receiving the preparation ply sections from the infeedconveyor and joining ends of two preparation ply sections to form a buttjoint splicing the two preparation plies together to form a continuouspreparation ply; an outfeed conveyor for feeding the continuouspreparation ply from the butt splicing machine; a gum strip applier forautomatically applying a gum strip on the butt joint of the continuouspreparation ply.
 27. A method of forming a continuous preparation ply ofthe type used to make vehicle tires, the continuous preparation plybeing made from preparation ply sections having nonmetallic cords, themethod comprising: automatically forming a first butt joint splicing twopreparation plies together to form a continuous preparation ply havingnonmetallic cords that extend in a direction substantially parallel tothe butt joint; and automatically placing a gum strip on the first buttjoint.
 28. The method of claim 27 further comprises: automaticallyconveying the continuous preparation ply after forming the first buttjoint; automatically forming a second butt joint splicing twopreparation plies together to form a further continuous preparation plyhaving nonmetallic cords that extend in a direction substantiallyparallel to the butt joint; and automatically placing a gum strip overthe first butt joint.
 29. The method of claim 28 wherein the steps ofautomatically forming the second butt joint and automatically placingthe gum strip over the first butt joint occur substantiallysimultaneously.
 30. The method of claim 28 wherein the step of placingthe gum strip on the first butt joint further comprises: automaticallyconveying the gum strip to a pickup position; automatically picking upthe gum strip and conveying it to a ready position; and automaticallyapplying the gum strip to the first butt joint.
 31. The method of claim30 further comprising automatically pressing the gum strip against thebutt joint with a desired force.